Particle beam energy changing device , particle beam therapy system with it , and particle beam energy changing way

摘要

And change the energy at a high speed, to provide a particle beam energy changing system noise is low. By varying the thickness of the attenuation body that attenuates the energy of the particle beam, changing a first energy to change the energy of the particle beam passing through device and a second energy changing unit has a first energy particle beam modifier and the second is disposed so as to pass through the energy changing unit, the maximum value of the first energy modifier of the attenuation is set smaller than the maximum value of the second energy modifier attenuation.